**Core Concept**
The child's presentation with fever, altered sensorium, purpuric rashes, and hypotension is suggestive of Hemolytic Uremic Syndrome (HUS), a complication of Shiga toxin-producing Escherichia coli (E. coli) infection. HUS is characterized by microangiopathic hemolytic anemia, thrombocytopenia, and acute kidney injury.

**Why the Correct Answer is Right**
The treatment of choice for HUS is supportive care, focusing on maintaining renal perfusion, correcting electrolyte imbalances, and managing hypertension. The primary goal is to prevent further renal injury and support the child's kidneys during the recovery phase. **Fluid resuscitation** is crucial to maintain blood pressure and ensure adequate renal perfusion. In addition, **dialysis** may be required in severe cases to manage electrolyte imbalances and fluid overload.

**Why Each Wrong Option is Incorrect**
**Option A:** Antibiotics are not the primary treatment for HUS, as the condition is caused by a toxin rather than bacterial infection.
**Option B:** Corticosteroids are not typically used in the treatment of HUS, as they do not address the underlying pathophysiology.
**Option C:** Plasmapheresis may be considered in some cases of HUS, but it is not the treatment of choice and is not indicated in this scenario.

**Clinical Pearl / High-Yield Fact**
It is essential to distinguish HUS from Thrombotic Thrombocytopenic Purpura (TTP), another microangiopathic disorder. TTP is characterized by thrombocytopenia, renal failure, and neurological symptoms, but it often presents with more severe neurological manifestations and is more likely to respond to plasma exchange therapy.

**Correct Answer:** C. Supportive care, including fluid resuscitation and close monitoring of renal function, is the treatment of choice for HUS.